Impact wrench



March 22, 1932. c J MCCARTHY IMPACT WRENCH Filed April 8, 1950 INVENTEIR Patented Mar. 22, 1 932 UNITED. STATES ATENT orFlcE 1 CHARLES J. MCCARTHY, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR OEONE-HALF 'TO MILTON .T. WESTON, OF NEW'YOBK,.N. Y. Y

IMPACT WRENCH Application filed April 8, 1930. Serial No. 442,581.

My invention relates to an improvement in impact Wrenches for use in applying nuts to and removing them from bolts and has particular reference to a type of wrench adapted for use in very restricted places where the regular type of wrench can not be used because of the limited movement of the wrench handle or where it can not be applied to the nut at all. At present it is customary, under these restricted circumstances,to use a chisel and hammerthe chisel being held in contact with a corner of the nut. This method not only injures the nut but is not adequately effective in setting the nut sufliciently tight to meet modern high pressure requirements.

The object of my invention is, therefore, to

provide an impact wrench which is especially adapted for use in limited spaces and which is simple and inexpensivein construction and which enables the user to set up the nut as securely as may be necessary and without injury to the nut.

My invention is fully described in the following specifications and clearly shown in the accompanying drawings in which similar numerals refer to similar parts in all of thewhich I have shown with an open throat but it may be of any of the usual types such as socket, alligator, adjustable, ratchet, etc. The head 1 is provided with a rela tively short shank 2 .terminatingin-a disc :3 which may be approximately the same, thickness axially as the head 1. Pivoted to this disc 3, by means of a pin 4, is an impact bar 5 whose function is to transmit the impact from a hammer or from the impact member 6 to the disc 3. The lower end of the impact bar 5 is slotted to fit over the acenterfin tightening the nut. In the construction shown and described, the pin- 4 does not receive any of the impact strains and is therefore relatively small in diameter beingintended only as a convenient means of holding the two memberstogether. I have shown this pin 4: as an ordinary bolt which can be easily and quickly replaced if'lost.

While it might be possible to make the pin 4: heavy enough to withstand the successive impacts, I believe the construction shown and described is preferable. The impact member 6 previously referred to, is desirable in places so limited that a hammer can not be conveniently used or where it is a par ticular advantage to be able to transfer the wrench head from one position to another with one hand and simultaneously guide the impact bar 5 and deliver a blow with the other hand. This impact member 6 is designed to fit freely over theend of the imof the wrench is applied to a nut and successive blows are delivered to the upper end of the impact bar 5 by means of an ordinary hammer or by the impactmember 6. As the nut is turned in the process, the head of the wrench is shifted to a new position on the nut and the operationcontinued until the nut is set up tight.

In practice, these impact wrenches will be supplied in sets, each set comprising several. wrench heads 1, each with a -different size of throat but all with identical shanks. Therefore only one impact bar 5, with or without impact member 6, will be required It is instantly removable with each set since any one of the wrench heads may be readily substituted by simply removing the pin 4.

I believe my invention to be new and desire to secure by Letters Patent:

1. In an impact Wrench the combination with a wrench head having a disc-sha ed shank integral therewith, of an im act ar pivotally engaging said disc-shape shank, the effective engaging surface of said impact bar conforming to the periphery of the said disc-shaped shank to present a maximum of impact area.

2. In an impact wrench the combination with a wrench head having a disc-shaped shank integral therewith, of an impact bar pivotally engaging said disc-shaped shank, the effective engaging surface of said impact bar conforming to the periphery of the said disc-shaped shank to present a maximum of impact area. and means for detachably connecting said impact bar to said disc-shaped shank.

Signed at New York in the county of New York and State of New York this 5th day of April A. D. 1930.

, CHARLES J. MCCARTIIY. 

